Dual load path pin clevis joint

ABSTRACT

A novel dual load path connector for pivotally joining a movable member to a structural member, is described which comprises a pair of spaced apart lugs attached to a first of the members, each of the lugs including an outwardly projecting boss, a clevis disposed between the lugs and attached to the first member, a pivot pin, received by the lugs and clevis, which may support a self-aligning bearing between the ends of the clevis, and a connecting link assembly including a first connecting link pivotally supported at a first end on the pin and connected at the other end to the second member, and a pair of second connecting links pivotally supported at respective first ends on the bosses and at the second ends to the second member, the first connecting link, pin and clevis providing a first load bearing path between the structural and movable members, and the second connecting links, bosses and lugs providing a second load bearing path. In a further embodiment, two pairs of spaced apart lugs are attached to the first member and a pair of flanged bushings are received by the respective lug pairs to provide a first load bearing path along the first connecting link, pin and one lug pair, and a second load bearing path along the second connecting links, bushings, and the other lug pair; projecting bosses may be provided on one lug pair to functionally replace the flanged bushings in the second load bearing path.

RIGHTS OF THE GOVERNMENT

The invention described herein may be manufactured and used by or forthe Government of the United States for all governmental purposeswithout the payment of any royalty.

This is a division of application Ser. No. 700,857 filed Feb. 12, 1985,now U.S. Pat. No. 4,786,202.

BACKGROUND OF THE INVENTION

The present invention relates generally to multiple load path connectorsfor fail-safe structural or load carrying mechanical joints and moreparticularly to a novel pinned clevis or double lug pair connectionwherein two separate load bearing paths are provided to carry a load ina fail-safe manner, one path carrying the load upon failure of theother.

Prior attempts to provide multiple load path joint connectors haveincluded use of a pin-within-a-pin arrangement and dual clevis or lugs.Also, large diameter pins have been used to provide a low stress leveland extended safe life design. These solutions may ordinarily besuitable when sifficient space exists for their installation. However,the use of large diameter pins requires large lug or clevis dimensions,and, if bolt clamp-up is desired for preloads in reducing bolt bendingstresses, large size bolt heads and nuts are also required. For certainapplications, such as in the mechanical linkages for movable airfoils onaircraft, unlimited working space and weight allowance are notavailable. Multiple load path connections may nevertheless be requiredfor safe life aircraft design for redundant structural or mechanicalconnections in areas where a single failure may result in loss of theaircraft.

The present invention provides a novel single pin structural ormechanical joint including a primary and a standby load path across thejoint. The pivotal connector configuration disclosed herein may beapplicable to simple pin joints or to self-aligning joints requiringrotational alignment about axes other than the pin axis. The inventionprovides a mechanical joint which may include both safe life and dualload path characteristics and which may be inspected for componentfailure without disassembling the joint. Further, the present inventionavoids space availability problems characteristic of existing structureswherein space for self-aligning joints in a diametrical direction may belimited, which may be characteristic of certain existing thin wingfighter aircraft, by using slightly increased amount of space in anaxial direction which is often available.

It is, therefore, a principal object of the present invention to providean improved multiple load path connector.

It is a further object of the invention to provide a dual load path,fail safe, single pin connector for structural or mechanical joints.

It is a further object to provide a self-aligning dual load path pivotalconnector for control linkage or support for movable airfoils onaircraft.

These and other objects of the present invention will become apparent asthe detailed description of certain representative embodiments thereofproceeds.

SUMMARY OF THE INVENTION

In accordance with the foregoing principles and objects of the presentinvention, a novel dual load path connector of pivotally joining amovable member to a structural member, is described which comprises apair of spaced apart lugs attached to a first of the members, each ofthe lugs including an outwardly projecting boss, a clevis disposedbetween the lugs and attached to the first member, a pivot pin, receivedby the lugs and clevis, which may support a self-aligning bearingbetween the ends of the clevis, and a connecting link assembly includinga first connecting link pivotally supported at a first end on the pinand connected at the other end to the second member, and a pair ofsecond connecting links pivotally supported at respective first ends ofthe bosses and at the second ends to the second member, the firstconnecting link, pin and clevis providing a first load bearing pathbetween the structural and movable members, and the second connectinglinks, bosses and lugs providing a second load bearing path.Alternatively, a pair of spaced apart fail safe lugs attached to thefirst member and a pair of flanged bushings received by the lugs may beutilized to provide a first load bearing path along the first connectinglink, pin and lugs and a second load bearing path along the secondconnecting links, flanged bushings, and lugs. In a further embodiment,two pairs of spaced apart lugs are attached to the first member and apair of flanged bushings are received by the respective lug pairs toprovide a first load bearing path along the first connecting link, pinand one lug pair, and a second load bearing path along the secondconnecting links, bushings, and the other lug pair: projecting bossesmay be provided on one lug pair to functionally replace the flangedbushings in the second load bearing path. In each embodiment including abearing the second link members may be pivotally connected with largetolerances to permit the first link to pivot about an axis perpendicularto the axis of the pin to impart a degree of self-alignability to theconnector.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more clearly understood from the followingdetailed description of certain representative embodiments thereof readin conjunction with the accompanying drawings wherein:

FIG. 1 is an axial sectional view of an embodiment of the presentinvention comprising a dual load path pin and clevis joint.

FIG. 2 is an axial sectional view of an embodiment including a pinnedjoint with bushings and safe life lugs.

FIG. 3 is an axial sectional view of an embodiment including double lugpairs and bushings.

FIG. 4 is an axial sectional view of an embodiment including double lugpairs, one pair including boss projections.

FIG. 5 is an axial sectional view of a non-self-aligning pinned jointwith bushings and safe life lugs.

FIG. 6 is an axial section view of a non-self-aligning pinned jointincluding double lug pairs and bushings.

FIG. 7 is an axial sectional view of a non-self-aligning pinned jointincluding double lug pairs, one pair including boss projections.

DETAILED DESCRIPTION

Referring now to FIG. 1, shown therein is a sectional view of oneembodiment of the present invention comprising a self-aligning pinnedjoint including a clevis and lug pair to provide a dual load path. Dualload path joint 10 may preferably comprise a connecting member in theform of a clevis 11 and a pair of lugs 12,13 on either side of clevis 11for making connection between a load path linkage assembly 14 and a loadcarrying or structural member 15. Clevis 11 and lugs 12,13 may be joinedto structural member 15 conventionally, as by bolts 16 or the like. Lugs12,13 include boss protrusions 12a,13a machined thereon for carryinglinkage assembly 14 in part as hereinbelow detailed.

The multiple load path linkage assembly 14 may comprise three linkagemember sets each, including a center member assembly 17 between twoouter member assemblies 18a, 18b, separated by spacers 19a,b, assuggested in FIG. 1. Linkage member sets 17,18a,18b, and 19a,19b may beconnected seriatim by bolts, pivot pins or the like as representedschematically by the broken centerline 20. The function of the linkagemember assembly 14 is to feed the load from or into joint 10 fortransfer from or to structural member 15 through clevis 11 andalternatively through lugs 12,13. The connecting end of center memberassembly 17 of linkage assembly 14 includes a self-aligning bearing 21received between the ends of clevis 11 and supported on transverselydisposed threaded pin 22 along assembly axis A through the eyelets ofclevis 11. The connecting ends of outer member assemblies 18a,18b oflinkage assembly 14 are received on boss protrusions 12a,13a,substantially as shown in FIG. 1. A nut 23 on threaded pin 22 securesthe assembly together as shown.

The center linkage member 17 carried on self-aligning bearing 21comprises the normal load carrying member in the linkage assembly; theouter members 18a,18b, which may preferably include oversize holes forreceiving boss protrusions 12a,13a, comprise the alternate or standbyload bearing members. The normal or primary load bearing path istherefore along center member 17, self-aligning bearing 21, pin 22, andclevis 11 to load carrying structural member 15. The standby load pathalong outer member assemblies 18a,18b, bosses 12a,13a and lugs 12,13assumes the load upon failure of an element along the primary load path.The pivotal connections between members 18a,18b with bosses 12a,13a maybe characterized by large assembly clearances to permit some rotation ofcenter member 17 on self-aligning bearing 21 about an axis perpendicularto axis A, in order for joint 10 to be self-aligning with respect to thedirection of load application.

FIG. 2 illustrates an axial sectional view of a pinned joint 25including bushings and safe life lugs. In joint 25, the primary loadpath is along center linkage member assembly 27 pivotally supported onpin 28 through a self-aligning bearing 29 in fashion similar to thejoint 10 configuration of the FIG. 1 embodiment. The secondary load pathlinkage member assemblies 30a,30b are pivotally connected to safe lifelugs 31a,31b through a pair of flanged bushings 32a,32b received by theeyelets of lugs 31a,31b and enclosing self-aligning bearing 29therebetween. As with joint 10 of FIG. 1, the assembly clearances oflinkage members 30a,30b may be large to allow some pivoting of linkagemember 27 on self-aligning bearing 29, thereby allowing the entire joint25 to be self-aligning.

FIG. 3 presents an alternative configuration similar to that shown inFIG. 2 and including dual lug pairs for redundancy rather than safe lifelugs. Accordingly, joint 34 of FIG. 3 includes outer lugs 35,36 and aninner lug 37 carrying a pair of flanged bushings 38a,b on threaded pin39. Self-aligning bearing 41 is pivotally supported on pin 39 andcarries one end of center link member assembly 42. The connecting endsof outer link member assemblies 43a,43b are pivotally connected on theflanges of bushings 38a,b. Therefore, center link member assembly 42,self-aligning bearing 41 and inner lug 37 may comprise one (primary)load path to a structural load carrying member (not shown), and outerlink member assemblies 43a,b, bushings 38a,b and outer lugs 35,36 maycomprise the alternate or standby load path.

FIG. 4 presents a joint 44 similar to that of FIG. 1, but includes dualload path lug pairs comprising outer lugs 45,46 and inner lugs 47,48 andboss projections 47a,48a on the inner lug pair. Accordingly, in joint 44of the FIG. 4 embodiment, the primary load path is along center linkmember assembly 52, self-aligning bearing 51, pin 49 and outer lugs45,46 to the structural load bearing member (not shown). The standbyload path is along outer link member assemblies 53a,53b, bosses 47a,48aand inner lugs 47,48. Bosses 47a,48a included on the inner surfaces oflugs 47,48 immediately adjacent self-aligning bearing 47 providesomewhat greater tolerance limits at the outer lugs 45,46 along thesecondary or standby load path, which may give center linkage assembly52 somewhat more rotational freedom on self-aligning bearing 51, andconsequently somewhat greater degree of self-alignability to joint 44,than that which characterizes the other described embodiments.

FIG. 5 illustrates an axial sectional view of a non-self-aligning, dualload path pinned joint 55 including bushings and safe life lugs. Injoint 55, the primary load path is along center linkage member assembly58 pivotally supported on pin 59 to safe life lugs 57a,57b. Thesecondary load path is along outer linkage member assemblies 60a,60bwhich are pivotally connected to lugs 57a,57b through a pair of flangedbushings 56a,56b received by the eyelets of lugs 57a,57b.

FIG. 6 presents an alternative non-self-aligning configuration includingdual lug pairs for load path redundancy rather than safe life lugs.Accordingly, joint 61 of Fgiure 6 includes outer lugs 62a,62b and innerlugs 63a,63b carried on a pair of flanged bushings 64a,64b and threadedpin 65. Pin 65 carries one end of center link member assembly 66. Theconnecting ends of outer link member assemblies 67a,67b are pivotallyconnected on the flanges of bushings 64a,64b. Therefore, center linkmember assembly 66, pin 65 and inner lugs 63a,63b may comprise theprimary load path to a structural load carrying member (not shown), andouter link member assemblies 67a,67b, bushings 64a,64b and outer lugs62a,62b may comprise the standby load path.

FIG. 7 presents a non-self-aligning joint 71 including dual load pathlug pairs comprising outer lugs 72a,72b and inner lugs 73a,73b and bossprojections 74a,74b on the inner lug pair. Accordingly, in joint 71, theprimary load path is along center link member assembly 76, pin 75 andouter lugs 72a,72b to the structural load bearing member (not shown).The standby load path is along outer link member assemblies 77a,77b,bosses 74a,74b and inner lugs 73a,73b.

In each of the described embodiments, a secondary or standby load paththrough the joint provides means to carry a load through the joint inthe event of failure of an element along the primary load carrying path.It is instructive to note that the secondary load paths of the joints ineach of the described embodiments will carry the load in the event offailure of the pin, and even if the pin is removed.

The present invention therefore provides a novel dual load path andself-aligning pinned connector for pivotally movable, load carryingjoints. It is understood that certain modifications to the invention asdescribed may be made, as might occur to one with skill in the field ofthis invention, within the scope of the appended claims. Therefore, allembodiments contemplated hereunder which achieve the objects of thepresent invention have not been shown in complete detail. Otherembodiments may be developed without departing from the spirit of theinvention or from the scope of the appended claims.

We claim:
 1. A dual load bearing path connector for pivotally joining amovable member to a structural member, comprising:(a) a pair of spacedapart lugs, each said lug including at a first end thereof means forattachment to one of said movable member and said structural member,each said lug further including at a second end thereof means definingan eyelet; (b) a pair of flanged bushings received by said lugs withinrespective eyelets thereof; (c) a pivot pin received through saideyelets of said lugs and said bushings; (d) a self-aligning bearing,supported on said pin between said flanged bushings; (e) a firstconnecting link pivotally supported at a first end on said bearing, anddisposed for operative connection at a second end to the other of saidmovable member and said structural member, said first connecting link,bearing, pin and lugs providing a first load bearing path between saidstructural member and said movable member: and (f) a pair of secondconnecting links, pivotally supported at respective first ends oncorresponding flanges of said flanged bushings, and disposed foroperative connection at respective second ends to the other of saidmovable member and said structural member, said second connecting links,flanged bushings, and lugs providing a second load bearing path betweensaid structural member and said movable member.
 2. The connector asrecited in claim 1 wherein each of said second connecting links includesan oversize hole for receiving said flanges on said bushings, therebypermitting said first link to pivot on said bearings about an axisperpendicular to the axis of said pin whereby said connector may beself-aligning.
 3. The connector as recited in claim 1 further comprisingmeans for connecting said second connecting links to said firstconnecting links for movement therewith.
 4. A dual load bearing pathconnector for pivotally joining a movable member to a structural member,comprising:(a) a first pair of spaced apart lugs, each said lugincluding at a first end thereof means for attachment to one of saidmovable member and said structural member, each of said first pair oflugs further including at a second end thereof means defining an eyelet;(b) a second pair of spaced apart lugs disposed between said first pairof lugs, each of said second pair of lugs including at a first endthereof means for attachment to said one of said movable member and saidstructural member, each of said second pair of lugs further including ata second end thereof means defining an eyelet; (c) a pair of bushingsreceived by said first and second lug pairs within respective eyeletsthereof, each of said bushings including a flange: (d) a pivot pinreceived through said eyelets of said first and second lug pair and saidbushings; (e) a self-aligning bearing, supported on said pin betweensaid bushings; (f) a first connecting link pivotally supported at afirst end on said bearing, and disposed for operative connection at asecond end to the other of said movable member and said structuralmember, said first connecting link, bearing, pin and second lug pairproviding a first load bearing path between said structural member andsaid movable member; and (g) a pair of second connecting links,pivotally supported at respective first ends on corresponding saidflanges of said bushings and disposed for operative connection atrespective second ends to the other of said movable member and saidstructural member, said second connecting links, bushings, and first lugpair providing a second load bearing path between said structural memberand said movable member.
 5. The connector as recited in claim 4 whereineach of said second connecting links includes an oversize hole at thefirst end thereof for receiving a corresponding said flange therebypermitting said first link to pivot on said bearing about an axisperpendicular to the axis of said pin whereby said connector may beself-aligning.
 6. The connector as recited in claim 4 further comprisingmeans for connecting said second connecting links to said firstconnecting links for movement therewith.
 7. A dual load bearing pathconnector for pivotally joining a movable member to a structural member,comprising:(a) a first pair of spaced apart lugs, each said lugincluding at a first end thereof means for attachment to one of saidmoveable member and said structural member, each of said first pair oflugs further including at a second end thereof means defining andeyelet; (b) a second pair of spaced apart lugs disposed between saidfirst pair of lugs, each said lug including at a first end thereof meansfor attachment to said one of said movable member and said structuralmember, each said second lug including at a second end thereof meansdefining an eyelet and an inwardly projecting boss; (c) a pivot pinreceived by the eyelets of said first and second lug pairs; (d) aself-aligning bearings supported on said pin between the bosses; (e) afirst connecting link pivotally supported at a first end on saidbearing, and disposed for operative connection at a second end to theother of said movable member and said structural member, said firstconnecting link, bearing, pin and first lug pair providing a first loadbearing path between said structural member and said movable member; and(f) a pair of second connecting links, pivotally supported at respectivefirst ends on corresponding said bosses and disposed for operativeconnection at respective second ends to the other of said movable memberand said structural member, said second connecting links, bosses andsecond lug pair providing a second load bearing path between saidstructural member and said movable member.
 8. The connector as recitedin claim 7 wherein each of said second connecting links includes anoversize hole at the first end thereof for receiving said bosses therebypermitting said first link to pivot on said bearing about an axisperpendicular to the axis of said pin whereby said connector may beself-aligning.
 9. The connector as recited in claim 7 further comprisingmeans for connecting said second connecting links to said firstconnecting links for movement therewith.
 10. A dual load bearing pathconnector for pivotally joining a movable member to a structural member,comprising:(a) a pair of spaced apart lugs, each said lug including at afirst end thereof means for attachment to one of said movable member andsaid structural member, each of said lugs further including at a secondend thereof means defining an eyelet; (b) a pair of flanged bushingsreceived by said lugs within respective eyelets thereof; (c) a pivot pinreceived through said eyelets of said lugs and said bushings; (d) afirst connecting link pivotally supported at a first end on said pin,and disposed for operative connection at a second end to the other ofsaid movable member and said structural member, said first connectinglink, pin and lugs providing a first load bearing path between saidstructural member and said movable member; and (e) a pair of secondconnecting links, pivotally supported at respective first ends oncorresponding flanges of said flanged bushings, and disposed foroperative connection at respective second ends to the other of saidmovable member and said structural member, said second connecting links,flanged bushings, and lugs providing a second load bearing path betweensaid structural member and said movable member.
 11. The connector asrecited in claim 10 further comprising means for connecting said secondconnecting links to said first connecting links for movement therewith.12. A dual load bearing path connector for pivotally joining a movablemember to a structural member, comprising:(a) a first pair of spacedapart lugs, each said lug including at a first end thereof means forattachment to one of said movable member and said structural member,each of said first pair of lugs further including at a second endthereof means defining an eyelet; (b) a second pair of spaced apart lugsdisposed between said first pair of lugs, each of said second pair oflugs including at a first end thereof means for attachment to said oneof said movable member and said structural member, each of said secondpair of lugs further including at a second end thereof means defining aneyelet; (c) a pair of bushings received by said first and second lugpairs within respective eyelets thereof, each of said bushings includinga flange; (d) a pivot pin received through said eyelets of said firstand second lug pairs and said bushings; (e) a first connecting linkpivotally supported at a first end on said pin, and disposed foroperative connection at a second end to the other of said movable memberand said structural member, said first connecting link, pin and secondlug pair providing a first load bearing path between said structuralmember and said movable member; and (f) a pair of second connectinglinks, pivotally supported at respective first ends on correspondingsaid flanges of said bushings and disposed for operative connection atrespective second ends to the other of said movable member and saidstructural member, said second connecting links, bushings, and first lugpair providing a second load bearing path between said structural memberand said movable member.
 13. The connector as recited in claim 12further comprising means for connecting said second connecting links tosaid first connecting links for movement therewith.
 14. A dual loadbearing path connector for pivotally joining a movable member to astructural member, comprising:(a) a first pair of spaced apart lugs,each said lug including at a first end thereof means for attachment toone of said movable member and said structural member, each of saidfirst pair of lugs further including at a second end thereof meansdefining an eyelet; (b) a second pair of spaced apart lugs disposedbetween said first pair of lugs, each of said second pair of lugsincluding at a first end thereof means for attachment to said one ofsaid movable member and said structural member, each of said second pairof lugs further including at a second end thereof means defining aneyelet, each of said second lug pair including an inwardly projectingboss; (c) a pivot pin received through the eyelets of said first andsecond lug pairs; (d) a first connecting link pivotally supported at afirst end on said pin, and disposed for operative connection at a secondend to the other of said movable member and said structural member, saidfirst connecting link, pin and first lug pair providing a first loadbearing path between said structural member and said movable member; and(e) a pair of second connecting links, pivotally supported at respectivefirst ends on corresponding said bosses and disposed for operativeconnection at respective second ends to the other of said movable memberand said structural member, said second connecting links, bosses andsecond lug pair providing a second load bearing path between saidstructural member and said movable member.
 15. The connector as recitedin claim 14 further comprising means for connecting said secondconnecting links to said first connecting links for movement therewith.